Both their previous matches got away from the British rink after the interval, but they maintained their momentum here.
Points were traded in the sixth and seventh ends before Morrison – growing in stature by the minute – delivered another two to move her side four clear going into the penultimate end.
Canada looked devoid of ideas. Homan, for whom Olympic gold has proved elusive throughout a stellar career, was floundering. One in the ninth left them needing a miracle but GB were not of a mind to let this one go.
The women will look to continue their unlikely revival on Sunday against another fancied rink, Sweden (13:05 GMT).
They have six more round-robin matches to play, with a total of five or six wins potentially enough to clinch a semi-final place.
And GB’s men are next on the ice, playing their fourth match of nine against Czech Republic at 13:05 GMT on Saturday.